The Saint-Louis River is a tributary of the Valin River, flowing on the northwest shore of the Saint Lawrence River, in the unorganized territory of Mont-Valin and the municipality of Saint-David-de-Falardeau, in the Le Fjord-du-Saguenay Regional County Municipality, in the administrative region of Saguenay-Lac-Saint-Jean, in the Province of Quebec, in Canada.

The forest road R0201 serves most of the hydrographic slope of the Saint-Louis river, for the needs of forestry and recreational tourism activities. The mouth of this river flows to the northwest limit of the Monts-Valin National Park.^[1][2][3]

Forestry is the main economic activity in the sector; recreational tourism, second.

The surface of the Saint-Louis River is usually frozen from the end of November to the beginning of April, however the safe circulation on the ice is generally made from mid-December to the end of March.

Geography

The main watersheds neighboring the Saint-Louis river are:

• North side: Nisipi River, Shipshaw River, Tête Blanche River, Onatchiway Lake, Little Onatchiway Lake;
• East side: Martin-Valin Lake, Sainte-Marguerite River, North Arm, Moncouche lake;
• South side: Valin River, Shipshaw River, rivière des Outardes, North arm, Canoe arms, arm of Hell, Fournier Arm;
• West side: canoe arms, Lake La Mothe, Étienne River, Tchitogama Lake, White River, Shipshaw River, Péribonka River.^[1]

The Saint-Louis river takes its source from an unidentified lake (length: 1.7 metres (5 ft 7 in); altitude: 691 metres (2,267 ft)). A mountain peak in the southwest reaches 800 metres (2,600 ft) of elevation. This source is located in the unorganized territory of Mont-Valin at:

• 2.0 kilometres (1.2 mi) West of Moncouche Lake;
• 18.7 kilometres (11.6 mi) South-West of lake Poulin-De Courval;
• 24.2 metres (79 ft)) east of a bay of La Mothe lake which is crossed to the south by the Shipshaw River;
• 38.9 kilometres (24.2 mi) North of the mouth of the Valin river (confluence with the Saguenay River).^[1] · ^[4]

From the head lake, the Saint-Louis river flows over 48.9 kilometres (30.4 mi), entirely in the forest zone, according to the following segments:

Upper course of the Saint-Louis river (segment of 28.6 kilometres (17.8 mi))

• 2.9 kilometres (1.8 mi) towards the North, then towards the West by crossing Lac Croteau (length: 1.6 kilometres (0.99 mi); altitude: 627 metres (2,057 ft)) on its full length to its mouth;
• 3.5 kilometres (2.2 mi) westwards, up to a bend in the river;
• 5.6 kilometres (3.5 mi) towards the South-West by meandering, up to the Céline stream (coming from the North);
• 16.6 kilometres (10.3 mi) towards the South-West, then the South by collecting Le Gros Ruisseau at the end of the segment and meandering up to the women's stream (coming from the East);

Lower course of the Saint-Louis river (segment of 20.3 kilometres (12.6 mi))

• 10.5 kilometres (6.5 mi) towards the South-East by collecting the stream at Vimy (coming from the West) and the stream Alcide (coming from the West), up to the stream at La Raquette (coming from the Northeast);
• 5.3 kilometres (3.3 mi) towards the south by crossing Savard Falls at the end of the segment, up to Savard stream (coming from the West);
• 4.5 kilometres (2.8 mi) towards the South-East by entering the municipality of Saint-David-de-Falardeau and by forming a loop towards the North-East at the end of the segment, until the mouth of the river.^[1]

The Saint-Louis river flows at the bottom of a small bay on the west bank of the Valin River. This mouth is located at:

• 23.4 kilometres (14.5 mi) Southeast of La Mothe lake which is crossed by the Shipshaw river;
• 21.7 kilometres (13.5 mi) north of downtown Saguenay;
• 14.9 kilometres (9.3 mi) North of the mouth of the Valin river;
• 100.8 kilometres (62.6 mi) West of the mouth of the Saguenay river (confluence with the St. Lawrence river).^[1] · ^[5]

Toponymy

The term "Saint-Louis" is a family name of French origin.

The toponym of “Saint-Louis river” was formalized on December 5, 1968, at the Place Names Bank of the Commission de toponymie du Québec.^[2]